import { computed, onUnmounted, ref } from "vue"
import dayjs from "dayjs"

//封装倒计时函数
export const useCountDown = () => {
  //1,响应式的数据
  let timer = null
  const time = ref(0)
  //格式化时间为多少分多少秒
  const formatTime = computed(() => dayjs.unix(time.value).format('mm分ss秒'))
  //2.开启倒计时的函数
  const start = (currentTime) => {
    //编写倒计时函数
    //核心逻辑:每秒减一
    time.value = currentTime
    timer = setInterval(() => {
      time.value --
    }, 1000)
  }
  //组件销毁时，清除计时器
  onUnmounted(() => {
    timer && clearInterval(timer)
  })
  return {
    formatTime,
    start
  }
}